The present invention concerns the technical field of implantable devices, in particular to correct at least one vertebral level, optionally with fusion of said level, said devices comprising a rod, a flat elongate element and a device to secure said elongate element to said rod.
The rods are usually used in combination with an implant to correct at least one vertebral level, such as a screw and/or hook to receive said rod.
Said rods can be used in the treatment of scoliosis or for the treatment of degenerative pathologies. Different levels of degeneration are encountered e.g. at one vertebral level such as intervertebral disk disease or at two vertebral levels such as spondylolisthesis or several levels such as C- or S-scoliosis.
In these treatments the rod can be placed in contact with the vertebral level to be corrected via an elongate element which passes around at least one portion of a vertebral body and around said rod, and the ends of said elongate element can be held in place by a suture, knot or implantable securing device. Said securing device may for example comprise a housing to receive the rod and the elongate element wrapped around the rod, and clasping device to lock said rod and said elongate element in said housing. In general, the clasping device comprises a device to clamp said elongate element to prevent any movement thereof.
The disadvantage of clamping said elongate element is that it may generate early wear of said elongate element via abrasion, said elongate element generally being formed of fabric.
A further disadvantage of this securing device is that it does not allow adjustment of tensioning of the elongate element once the implantable device has been implanted at the vertebral level to be corrected since the elongate element is fully locked in place by the clamping device. Yet it is often necessary to adjust the correction provided by the rod that is linked to the elongate element, once the device has been positioned on the vertebral level to be corrected.
In addition, this type of device to secure an elongate element onto the rod is not easily reversible. It is most complex to unscrew the multiple screws to adjust correction at the vertebral level to be treated.
There is therefore a need for an implantable device, in particular to correct a vertebral level, comprising an elongate element and a device to secure said elongate element in a position encasing said rod allowing said elongate element to be tensioned around the rod once it has been secured in said encompassing position, without separating the securing device from the rod already positioned on a least one vertebral level to be corrected.
There is also a need for securing device that are easy to position and reposition.